Emissions traps are used to trap and thus remove emissions from exhaust gas to reduce discharge of emissions to the atmosphere. From time to time, emissions traps are “regenerated.” During such regeneration events, emissions trapped by an emissions trap are purged therefrom for further use of the emissions trap.
A soot trap is one type of emissions trap. A soot trap is used to trap and thus remove soot from exhaust exhaust. It is regenerated by burning off the soot trapped thereby.
A NOx trap is another type of emissions trap. A NOx trap is used to trap and thus remove NOx (i.e., oxides of nitrogen) from exhaust gas when the exhaust gas is relatively lean (i.e., has excess oxygen). The NOx trap is regenerated in the presence of a NOx-reducing agent [e.g., fuel, hydrogen (H2), carbon monoxide].